Akchagylian Hydrospheric Phenomenon in the Aspects of Deep Geodynamics

Hydrospheric disturbances are one of the defining elements of the development of both the stratigraphic scale and the scale of planetary periodization during the Late Cenozoic. The most exotic in paleogeographic and sedimentation-biotic terms is the Akchagylian basin – anomalously elongated deep to the north and characterized by a typology of transition from a brackish water regime to a semi-marine and marine one. The sea transgression in the Akchagylian time reached 200 and more meters, which could not but have a significant impact on the accumulation of precipitation and the climatic conditions of this period. On the basis of the detailed stratigraphic, structural-tectonic, palebiogeographic, and paleomagnetic analyzes, the boundaries and volume of the Akchagylian stage in the Eastern Paratethys region were revised. For the first time, the land-sea boundaries for this region during the period of the maximum of the Middle Pliocene (Akchagylian) transgression are distinguished. Based on the carried out regionalization, the concept of the “Akchagylian Phenomenon” received
planetological and geophysical assessment. A clear connection is shown between the development of the Akchagylian basin with different tectonic elements, and first of all, with the recently revealed giant deep mantle structure rotating counterclockwise.